Chill the far end, feed the near end

A chill at the lower arm so it freezes before the bearing boss, letting the boss riser feed the whole path.

A riser over the boss alone. It fed the boss and starved the arm, which was the last thing to freeze.

The arm was the thickest section and the furthest from the riser, which is the worst combination. Forcing directional solidification with one chill was cheaper than a second riser and it did not add cleanup.